One of the first social networking upstarts, MySpace, is facing continuing security problems that threaten to spoil many of the innovative features that make the site useful.

Hackers, spammers and Internet malcontents have turned many of the "group" sites, which are dedicated to interests such as home beer brewing, animal welfare and gay rights issues, into cyber-graffiti walls, filled with offensive comments and photographs.

Those trashing the group profiles are known as trolls, who delight in making a mess and try to one-up each another with aggressive vandalism. They post taunting videos on YouTube.com, egging each other on and making real-world threats.

It has left many MySpace users struggling to maintain order on their groups. They allege that MySpace has been lax in fixing several well-known glitches that persist on the site despite repeated efforts to contact security administrators. MySpace, which would not grant interviews for this story, contends it has beefed up its security department and does its best to patrol the site for misbehavior.

"Over the last two years, I have notified MySpace not only of the problems but given them possible solutions as well, but they have only responded with a thank you, but there never has been any result," said Corey Scott-Walton, of Sacramento, California, who runs a group for craft-beer enthusiasts.

Scott-Walton is one of several MySpace users who became fed-up with trolls and created their own tools for combating abuse.

One of the problems is a glitch that allows vandals to post comments on a group even when they aren't an approved member. Usually, a moderator must approve new people who join a group.

That glitch opens a door to two more. Another is "bombing," where dozens of empty comments can be posted in the group's discussion area using an automated tool. The boxes push down the real comments and create hundreds of empty comment pages, effectively ruining a conversation. Another problem is "pinning" where a new topic on a discussion thread can be pinned on any forum.

Even if the account of the vandal has been deleted, the offending posts are sort of halfway deleted, with no comments visible but page after page of blank space. Scott-Walton wrote a tool in Visual Basic called "Thread Cleaning" that allows moderators to delete those posts.

MySpace's terms of service forbid use of automated tools and scripts, but users say they've been left with no choice.

Another MySpace user who is a Web developer in Connecticut created a tool that will check his group every 20 seconds for spam and delete it. The Web developer, who did not want to be identified for fear of harassment, said he has used the "report abuse" feature hundreds of times.

"I've found that the more people that report an [abusive] account, the faster MySpace makes it go away," he said.

Trolls will often create hundreds of "sock-puppet" profiles that are used merely to harass other users. Once the particular profile has been shut down by MySpace, the troll will simply use another one to continue attacks.