As with Google Notebook you decide if clips are private or public. Sharing not a requirement. Read their policy, blog http://www.clipmarks.com/privacy-policy/ http://clipmarks.wordpress.com/
Search for experiences. No need to sit and wait for disaster - or expect disaster. Nothing indicates they are evil. Works pretty well. When they first appeared someone said it was a cool idea but must be hard to keep up interest for the community part - I agree though site is nicely build. Has improved a lot, Digg-like but clips? All I can say is I dont feel a great need to use Clipmarks but works ok.
Recently I think Google changed default setting with their Notebook from public to private. Turned out some people saved bank account etc. in public/indexed/searchable Notebooks! Same with Google Calendar, share or not is up to you.
Google Notebook is less flashy so may be try it out. Latest version is more useful than old, now easier to organize and work with during "noting". Something about being able to pop out collection window, a little new arrow do that. You will see.
Alternative to Evernote, Scrapbook which only works for Firefox is Net Snippets http://www.netsnippe....com/basic/index.htm
I read something about Yahoo/Flickr investigating what colors people react to - part of profiling. And Google knows everything already
If you keep personal/important data locally I dont think you need to worry. To worry about them getting your Gmail Address (of course you have more than one and use a special for sign-ups right?) is wasted time. Being careful about content like treating personal info differently than "public" is just good sense, always think about that. Same goes for local computer, if I stole yours tomorrow what will I get/learn? Encryption and similar thoughts of storageing sensitive info is way to go. Worst scenario with Clipmarks is they close down and you lose all content! Good idea to check if service is steaming ahead before signing up.
Also remember they could not care less about you, you are not interesting as a person. We are all simple IPs/advertising targets in the eyes of machinery. Perhaps some services are interested in your money/plastic card, encouraging you to sign up for "Pro" type of account. That is all. If you cant keep hands off the goodies and still dont trust "them" then spread wings. Use some Yahoo, some Google, some Clipmarks etc. Harder to profile worlds most interesting person unless of course there is a master service we dont know about yet, heh. Profiling for what purpose btw? Be careful not to exaggerate risk because of Big Brother/what if? lingo. If profiling is not used for evil but necessary advertising it is part of the service, like Google learning spelling mistakes and suggest more "intelligently" the more you use it - and of course "manipulating" search results based on my history. Probably also about advertising in the end.
Anti-phishing feature in Firefox/IE7 is nice right? You are aware each and every url is sent MS/Google? You think solution is to disable? Your ISP already has same info. Talking about profiling makes you dizzy... You end up frustrated, unplugging computer from internet so dont and definitly laugh at email harvesting. Gmail even have great spam filter should Clipmarks decide to sell addresses to spammers.[...personal info removed by moderator..]
Online identity matching real one is perhaps something to think about, must be if you are scared on behalf of email address. Actually you should go "Whatever, come get me" I hope you do.