Spammers are never far from a hot story, it seems, and in the past day they've been flooding Twitter with phoney messages about Iran and the latest iPhone 3.0 operating system.

In one campaign, the spammers apparently took their lead from a Mobile Crunch article about 20 things to check out in iPhone 3.0. They've set up fake Twitter accounts and posted Twitter messages that link to a Web site promoting male enhancement products. The Twitter messages say things like "iPhone OS 3.0 Just Launched. Here are 20 Things To Do With It," and are also being posted by some legitimate (and presumably hacked) Twitter accounts as well.

"The spammers lifted the Crunch title and rode its coattails," said FaceTime researcher Chris Boyd, who blogged about the issue on Thursday.

The plan, apparently, is to have the messages pop up when people search for info on Apple's iPhone, one of Twitter's top Trending topics on Thursday. Apple released the iPhone 3.0 OS on Wednesday.

Spammers are also trying to cash in on the intense interest in the disputed Iranian election, posting messages such as "Mousavi trend? omg stephen colbert hit a woman.earned $2,612 thanks to this to this." Mir Hossein Mousavi is the reformist politician whose defeat in last week's Iranian presidential contest has sparked mass protests.

Often they'll simply put a popular hashtag (the # sign followed by a keyword) or keyword in a message that has nothing to do with the topic in order to gain eyeballs, said Rik Ferguson, a researcher with Trend Micro.

As use of social media sites like Twitter and Facebook has mushroomed, so has their abuse. On Thursday Internet entrepreneur Marc Cuban said he would no longer allow employees to use Facebook, because viruses "are becoming so rampant" on the site.

Cuban owns the Dallas Mavericks and is chairman of HDNet.

Some security experts have suggested that Twitter give users a way to search for messages from more established users, but Boyd thinks that the company should do away with trending topics altogether. "It's a spam magnet list," he said in an instant message interview.

"High profile tech stories are a natural draw for Twitter spammers, and the 'trending topics' list unfortunately makes it easier for them to target whatever happens to be the main buzzwords of the day. They know people will click the link and the shortening services make it easier than ever to drop someone onto a spam page."

Not to be outdone, old-fashioned e-mail scammers are now sending out fake invitations to join Twitter that try to trick victims into downloading a malicious "invitation card" .zip file that's actually a worm program. Symantec first caught wind of this scam last month, according to Dermot Harnett, a Symantec analyst.

The "join Twitter" scam is not widespread and is rated a "low volume" problem, Harnett said.