- Facebook floated in May last year valued at $100bn, but its share price fell sharply - blamed partly on Nasdaq technical issues. Shares have since recovered and the company is now valued at more than $120bn.
- LinkedIn shares soared after its 2011 flotation on the New York Stock Exchange, almost doubling its expected valuation to $8.5bn. Today it is worth more than $26bn.
- Lastminute.com shares slumped after floating in 2000. It was bought out five years later for £577m, less than half the flotation price.
Last.fm has become the latest social network to reveal it is investigating the leak of some of its users' passwords.
A message posted on its website today has urged account holders to log in and change password as a precautionary measure.
The music streaming and statistics service had 30 million active users in March 2009.
Internet scammers have targeted LinkedIn users likely to be concerned about their account security following yesterday's claims that as many as six million passwords had been stolen by hackers.
Emails, such as this one seen by the BBC, claiming to be from "The LinkedIn Team" were sent to users asking them to confirm their email address by clicking a link.
But the BBC says the link only took recipients to a website selling 'counterfeit drugs'.
Millions of users of the social networking site LinkedIn have been told to reset their passwords after security information was stolen.
IT security and data protection firm Sophos said the leaked encrypted data does not include associated email addresses but warned that hackers will be working to crack the "unsalted" password hashes and "it is reasonable to assume that such information may be in the hands of the criminals".
Social networking website LinkedIn has provided these security tips following the reported theft of almost 6.5 million passwords. See the full statement here.
- Never change your password by following a link in an email
- Change your account passwords every few months
- Don’t use the same password on all the sites you visit
- Don’t use a word from the dictionary
- Never give your password to others or write it down
LinkedIn has provided an update on the reported theft of almost 6.5 million passwords. The social media website said it is "continuing to investigate" but that it has put measures in place for "the compromised accounts". A statement said:
Users affected by the theft will find that their password is no longer valid. They will receive an email explaining how to reset their passwords, but are warned not to do this by following any links in emails. LinkedIn did not say how many accounts were compromised.
Experts are advising LinkedIn users to watch out for scam emails that appear to be from the social networking site.
Adrian Chen from the Gawker website said the spam emails are likely to be slightly different in appearance. You should not give away any login details.
Users have also been advised to change their password to something unique, that they are not using on any other website. The nakedsecurity blog provides a guide on how to do this.
A consultant at IT security and data protection firm Sophos has said that the leak of six million passwords from LinkedIn does not include the associated email addresses.
But he warned that it is "reasonable to assume that such information may be in the hands of the criminals". He advised the following:
Social networking website LinkedIn has advised its users to "stay tuned" while it investigates reports that more than six million passwords have been stolen.
Internet experts have advised users to change their security details immediately after a file containing 6.5 million passwords was posted online.
Social networking website LinkedIn is looking into claims that the passwords of more than six million members have been stolen.
The site, which provides as social networking service for professionals, has in excess of 161 million members in more than 200 countries.