I've heard rumors that submitting your own articles to Socialbookmarking websites can hurt your website.
I've heard rumours about Ashlee Simpson, I wonder if they're true. Look at the terms and conditions of the main bookmarking sites - they all have a clause about spam e.g stumbleupon Accounts created with the primary intention to promote a product or service are considered "SPAM" and subject to termination unless expressly authorized in advance in writing by StumbleUpon. so, it's a grey area, in theory, anyone adding their own site is spamming. In practice, they'll turn a blind eye if you do it a little bit, but ban you if you get too big for your boots. But hurt your website - I don't see how - just get you banned from that service.
I've heard stuff like this a hell lot of times: something like "Can this off page factor hurt my website???" IMHO it definately CAN NOT. For example, i do not like yourwebsite.com and i post articles and other stuff over the net to hurt this website. Well its not plausible, because if it would, anyone could just drown a website if they wanted. No off page SEO factor can hurt your website...
Yes i agree this is too true, you can only really hurt yourself with on-page factors, or other services if they are verified by your website in some way. Otherwise any man and his dog could bring your website down in the rankings.