As long as you don't apply for an alliance with many clans simply for the sake of being more known and popular around the forum, then I think it's fine. I'm only an ally with three clans. All three of them because I'm cool with the leaders, and I try to post sometimes. I sometimes feel like posting a huge amount of posts there, but sometimes I can't seem to find a thread that's actually worth to post in. Possibly I might not have anything to post that'll continue the conversation.
So, basically, it depends.