Just how effective is communication on Twitter? If you want to get your messages noticed, a study reveals when you should plan your most informative missives for re-tweeting.

Just how effective is communication on Twitter? About 40 percent of Tweets are actually useless babble, but if you want to get your messages noticed, might want to log on early in the week, according to data released Wednesday.

Market research firm Pear Analytics was interested to find out if Twitter actually conveyed useful information or it was a spam-filled waste of time. They took 2,000 English-based Tweets over a two-week period, capturing the messages in half-hour increments. They then lumped them into six categories: news, spam, self-promotion, pointless babble, conversational and pass-along value.

Not surprisingly, about 40 percent of these 140-character musings were just pointless babble, though about 37.55 percent were placed in the conversational category. Coming in third was pass-along value, though that only secured 8.7 percent of Tweets. Self-promotion landed at 5.85 percent, about 3.75 percent was spam, and 3.6 percent was news.

"We thought the News category would have more weight than dead last, since this seems to be contrary to Twitter's new position of being the premier source of news and events," the study said. "Self-promotion was also less than expected, [which] may be enlightening to some folks, as there appears to be a flurry of companies and businesses joining Twitter to promote products and services."

But in addition to just sorting the messages, the firm also figured out what days and times are best for getting your Tweets noticed.

Do you want your message re-Tweeted? Your best bet is to post your message on Mondays or at 11:30 a.m. (Central time), the firm said.

Most of the news hit the micro-blogging site around 2 P.M. and on Tuesdays. (The group purposely did not include Michael Jackson-related news so as not to skew the results.)

Conversational Tweets, meanwhile, usually occurred between 2 and 4 P.M., and usually on Tuesdays. "Most people are busy on Monday catching up with work, so perhaps it takes until Tuesday to get into the swing of Twittering again," the firm said.

Spam? You're going to get that at all hours of the day, Pear found.

"With the new face of Twitter, it will be interesting to see if they take a heavier role in news, or continue to be a source for people to share their current activities that have little to do with everyone else," the study concluded.

Pear said it will be conducting this study every quarter to identify other Twitter trends.