ReTweet.com is a service based on retweets, the repeating of status messages on Twitter of people that you follow. ReTweet has about $1.4 million in funding no funding (e-mail from ReTweet) and their biggest competitor Tweetmeme has about ?650,000 ($926,000) in funding.
Both companies are really picking up steam in the ReTweeting business and TweetMeme does not like it. TweetMeme has threatened Mesiab Labs, the company behind ReTweet.com for copying their website design and copying their retweet button code.
The only problem with these two companies is that Twitter themselves are interested in getting into retweets too. If Twitter starts counting how many times status updates have been repeated and even creates a widget that showcases the count, these two companies will be out of luck.
Update: ReTweet is valuated at about $4 million by Leapfish.