Why bother colleague request, but no message?

[Michaela G.]

I get a fair amount of colleague requests from people, who don't send a message with it?

Why bother?

I don't understand why someone would want to collect colleagues, unless they actually have some common ground or have a question. It's not like Facebook and the number of colleagues doesn't matter. 

I personally ignore any requests that don't share a reason why they'd want to connect with me.