deleting inactive users

Over half of my users have no logged in in 90 days+. Should I delete them in order to have a better unique content ratio or are the additional pages of value since they're indexed?

I would never delete any member of your userbase, unless you've identified accounts that were created by automated spam bots.

most of them are from spam bots, but I am unsure of a good way to identify them.

When in doubt, I wouldn't spend much of your time dealing with removals.

I would enable your image verification on registration to help prevent bot sign-ups.

I agree I wouldn’t delete them unless you have truly identified them as spam bots.

On a site note, If you are getting a lot of spam bots, I would suggest using, NoSpam! mod over at vB.org. Since installing this I have only had 2 spammers, which were humans. I have this running on all my forums. This will basically stop any spambots from signing up.

i deleted about 10,000 members once. and i fully regret it.

i was running out of space at the time, and didn't have a budget for more storage, so i killed everything i could.

it earned me about 20kb of space. lol

Yikes - too bad you didn't do a backup first. But - we've all had horror stories like that back in the day.

I had a server go down because my credit card didn't take a $500 extra charge for extra bandwidth usage... while I was making affiliate sales of about $1000-$1500 a day. That's back when bandwidth was more expensive and I was just getting started... and when Google was a whole lot easier to manipulate than it is today.