LOL!! you are asking about the logo of popular social bookmark site ministry . Need to take permission form owner of that site.
Well, since you are talking about a logo / brand, it falls under Trademark laws, so you'll need to read up on those laws in your country. If you are in the USA, you can read up on trademark laws here: http://www.uspto.gov/trademarks/basics/index.jsp
if you are from the UK, you will need to catch up on UK Trademark / Copyright law. Similar to the US, but as with all legal issues, vary from country to country >>> http://www.ipo.gov.uk/tm.htm Prices to Trademark vary depending on the complexity of your trademark and which classes you want your trademark to be assigned to.
In reality, it is common for companies to register their logosRegistration can make your company logo, as well as photos or artwork associated with the label or advertising material. This happens often in the companys start-up or before the launch of a new product or an advertising campaign. Its really important. This might be helpful if copyrightservice[dot]co[dot]uk/protect/logo_copyright