• [Why did the British use Shrapnel rather than High Explosive at the Somme?] (http://www.reddit.com/r/AskHistorians/comments/2voe8g/ive_heard_the_british_made_a_major_mistake_at_the/)

I've answered this question exactly right here

There simply weren't enough HE shells and many of the shells, both HE and Shrapnel, were faulty. Shrapnel was, however, useful for cutting wire (though it had to be fused precisely), keeping the defenders in their fortifications, and constricting movement above ground behind the lines. The Germans lost the initiative when the Franco-British artillery forced them into their static positions and constricted their resupply and replacement.

EDIT:

• [The Somme & Verdun: fruitlessly wasteful, or painfully necessary?] (https://www.reddit.com/r/AskHistorians/comments/32t8bn/world_war_i_question_largescale_offensives_like/)
• [The Battle of the Somme in Franco-German Memory] (https://www.reddit.com/r/AskHistorians/comments/3bsihm/the_opening_of_the_battle_of_the_somme_happened/)

^ Some other answers I've given concerning the Somme