Not a professional historian, but I think I can shed some light on what happened in Romania.

By the late 1980s, Romania under Nicolae Ceausescu became one of the most repressive regimes in the Eastern Bloc, arguably second only to North Korea in its brutality (!). Ceausescu was extremely unpopular with the general population, and opposition to his rule was growing within the Communist Party itself, as evidenced by the Letter of the Six and the clandestine National Salvation Front (FSN) led by prominent Communist Party member Ion Iliescu.

In December 1989, Ceausescu's regime was overthrown in a violent revolution. Now the interesting part is that the revolution began as mass protests in major cities, but ended as a sort of coup d'etat. The Communist-dominated FSN seized power with support from the army, had Ceausescu executed, and initiated Romania's transition, arguing for gradual, step-by-step market reforms instead of the "shock therapy" method that some other Eastern Bloc countries used. Iliescu and the FSN subsequently won free but unfair elections in the spring of 1990 amid major protests. At the same time, a number of Ceausescu-loyalists (known as the CPEx Lot, which included Constantin Dascalescu, the prime minister at the time of the revolution), were put on trial for genocide; they were ultimately convicted of manslaughter. Dascalescu himself was sentenced to life in prison, but was released on medical grounds in 1996.

A democratic Constitution was adopted in 1991, and a new round of elections were held the following year. Around this time tensions grew within the FSN, as president Iliescu clashed with the more reformist prime minister Petre Roman; Iliescu and his supporters ended up leaving the FSN and founding the Democratic National Salvation Front (FDSN). Reforms continued at a relatively slower pace than in other Eastern European countries, and as such it could be argued that the early 1990s were a period of proto-democracy in Romania under governments that were dominated by former Communists, despite an increasingly powerful liberal and christian-democratic opposition. The FSN and FDSN eventually evolved into the present-day Democratic Liberal Party (PDL - centre right) and Social Democratic Party (PSD - centre left), respectively. Iliescu is still honorary president of the PSD.

Mods, please forgive me for not citing any sources.

I don't want to put this as a top-level reply, as it is not strictly within the rules, but there is no relevant post to reply to with it:

For a fictional example of East German communists dealing with the fall of communism, check out the film "Goodbye Lenin"

I'm not sure what's to provide in terms of sources since these are documented news events, but I guess good sources are the German federal fund for re-evaluation of the SED dictatorship and the federal center for political education.

In Germany, the SED (Sozialistische Einheitspartei Deutschlands, German unified/uniform socialist party) was actually officially dissolved before the final integration of the DDR (German Democratic Republic, East Germany) into the German Federal Republic. Its last leader, Egon Krenz, spent the last months of communist administration frantically trying to keep things things together after news came out that the regime had falsified local election results earlier in 1989 and massive protests erupted. The transition was fairly peaceful; the regime understood in late 1989 that after the opening of the Hungarian borders and the (possibly accidental) opening of the Berlin wall it could no longer exert absolute control. Throughout the previous years, the SED had governed with a veneer of pro forma democratic legitimacy, which after the 1989 unrests, it could no longer do. It lost the 1990 elections, resulting in the attachment of the DDR to West Germany.

So the party was re-formed in 1989 as the PDS - the "Party of Democratic Socialism", and received credible results in national elections as post-1990 it was able to attract leftist voters throughout Germany (although its main base was in the East, but also consisting of Germans who either felt a philosophical attachment to communism, who didn't feel other leftist parties were consistent enough, or who had never had a credible West German communist party to represent them).

Germany has had a tradition of moderate social democratic parties since the late 1800s, and the SPD under Gerhard Schröder took a similar pragmatic and centrist course as Tony Blair's "New Labour", which did not sit well with many in the left wings of that party. So the PDS merged with another leftist party formed by politicians disaffected with the ruling Red-Green coalition in 2005, into what is currently known as Die Linke (the left).

Much of the PDS' leadership was active to some degree in East German politics - its current leader, Gregor Gysi, was actually a well-known reformer in the late years of the DDR, and is a very accomplished speaker.

After the re-merger of Germany, there was a long and arduous process of investigation into wrongdoings of the SED regime, including the shootings of people attempting to flee, and espionage of citizens in both Germany. You have to remember that the Stasi, the DDR secret police, had so many informers ("inofficial collaborators", Inoffizielle Mitarbeiter) throughout both countries that even prominent politicians have been accused of working with them. So even though the SED's successor parties have integrated completely into the democratic process, there's a constant underlying discussion about whether and to what degree their leadership and members may have collaborated with the SED regime.

I know that in Moldova the first years after Perestroika and Glasnost were difficult for the small country. They switched to a parliamentary system with democratic parties dominating in the first elections. Like most FSU countries, their economies tanked and the Republic of Moldova was no different. Largely agrarian with little industry and the sudden loss of Soviet support, things got dicey. Their political system broke apart as people expecting democracy to be a cure-all, called for elections. Everyone voted communist again, hoping those "glorious" days would return. It was during this time that they lost a track of land east of the Nistru which was ethnically dominated by Russians. Supported by the Russians, this sliver of land became a nation only recognized by Russia and I think Iran as Transystria.

Read Charles King's The Moldovans in addition to whatever you can find on JSTOR.

Thanks for all the responses, everyone!! This has been very informative. I'm also glad to learn more of the various ways that Eastern Europe transitioned from communism, since they each transitioned in different ways and kept some elements of their communist eras into the 1990's.

One follow-question: Some communists were retired, jailed, executed, or simply moved onward in the 1990's. Did communists suffer from some level of being pariahs, ostracized, or even persecuted even though their parties may have continued in some more limited capacity?

Thanks again, everyone.

Former residents across 11 former Soviet states believe the dissolution was more harmful than beneficial, according to a Gallup poll

In Russia, they died. Privatization led to mass deaths of the working class. I could also link other stats regarding damage to industry and lives if you're interested but I think that falls behind the purview of your question; Globalization And Its Discontents has stats regarding this.

Also, again, the idea that the transition towards capitalism was popular (and, I think more importantly, that it was painless) is contestable. Romanians preferred it (data compiled by an anti-Communist group btw) Same with Eastern Germans and Hungarians. I have similar sources for Russians and other nations if you wish, and notably these views are expressed by former residents (and many times, significantly, by younger populations as well).

Your question has some assumptions built into the way you phrased it, so I though alternative information might interest you.

What about the western Communist parties like in Italy and France? How did they react? I recall something about the Italian Communist Party splitting over the NATO intervention in Yugoslavia, but that's about it....