Even if they allow you to use it it's still dupe content in Google's eyes and thus will tarnish the sites content value. The first site it appears on gets all the SEO juice and any other copies are only good for backlinking to get organic (click through) traffic to another page- it's generally bad practice to syndicate articles that are being used on sites like Wizzley, Squidoo, etc...
It doesn't damage the original article site it's on, (well it does as if it's not the ONLY copy out there the SEO value of it diminishes) but if, for example you wrote an article here then syndicated it (posted it anywhere else), Wizzley would get the original copy award, but the other copies you post will cost us, and your article/page SEO value- much like a one of a kind anything is a "collectors item" and anything with copies of it is simply that- a copy...
It can damage SEO "quality" on the site you copy it to (if the reverse is true i.e. write it here and post it on SQ it will (just an example, they won't allow it) be seen as a dupe content and flagged as a copycat- thus given no juice by Google.
You should always write (and is usually required and dupe content filters catch it) original content for these sites... for syndicated "backlink producing" articles use ezinearticles not a web 2.0 property, and don't post anything here that exists anywhere else- we need all the SEO juice and credit in Googles eyes as possible- we are, after all new in the realm and sites with high quality in check- get up the serps faster- faster serps means faster and more powerful indexing of our individual pages.
Jerrico
p.s. rewriting an article completely is the same as original content- fixing one up to try to make it original is tedious, a waste of time, and will often get a dupe flag if even 2% of the content remains from the original... When I want a rewrite of one of my articles I hire a ghostwriter to do it to assure I don't repeat myself, we have a section of the forum you can tap into the writers from who will ghostwrite for you for whatever they individually charge...
Personally I'd link from the original to the new rewritten one here, since their different but similar, you can bank on the original juice (the same works in reverse, but I try to link only one way, Google doesn't like what looks like a link exchange and are dinging sites for it according to the last recording I heard from Matt at Google)...
Jerrico