SMS verification is useless. Spammers have just as easy (if not easier) access to numbers as ordinary users.

That, and most people don't want to share their numbers with some site. For all they know, you are just collecting the numbers and reselling them.

I bet most people don't care. On a dating site for "fellow nerds" though, it might not fly.

Spammers increase conversions and activity on the site. I worked for a dating site and they condoned spammers that weren't out of control. Hell, they tacitly approved of hookers working the site as long as they weren't blatant.

If you're looking for a date, take the effort of going out and meeting someone. Online dating is a total waste of time for most people, unless you're looking for someone who sits at their computer all day.