Basically, many of the times when you read about the swahili coast you find that Mogadishu is usually referred to as being the northern-most state of the Swahili coast, and as being one of the cities that rose to prominence first. Why is it that Mogadishu is included in the Swahili coast despite the fact that in the modern day Mogadishu is not inhabited by Swahili nor is it in a nation with many swahili at all (It is Somali.) So is its inclusion indicative of it once being built and inhabited by Swahili, or does it mean something else?
I gave some Swahili coast history with some citations a few weeks ago, take a look here for the basics and background:
Mogadishu was part of the Swahili coastal trading culture at the height of that culture's influence. As the Omani trading empire collapsed, the last gasp was when the Omani sultan moved the capital to Zanzibar in the 1800s. I'm not 100% sure what time period Mogadishu was directly under the influence of the Swahili coastal culture, but it wasn't really ever a defined nation as we'd call it these days.
Hope that helps some.