There are huge number of blogs on the Internet, and many are on patents -- mostly American, and mostly on the legal aspects. Here are my favourite five blogs in the subject area, in no particular order.
The IPKat is a group blog consisting of eight individuals, who include Tufty the Cat and Jeremy Phillips, who I have met on occasion. Based in the UK and concentrating on European litigation, mainly in trade marks and patents, there are numerous, detailed posts, often with links to copies of the court decisions. If there is one blog you read to keep up to date with European case law in IP, this is it.
Ideas Uploaded is a site run by Tara Roskell, a freelance graphic designer who lives in Northamptonshire in the UK. There are lots of podcasts showing interviews with inventors, with discussions of creativity and how to commercialise inventions.
The Intellogist site has a blog with the strapline "Patent search questions, expert answers". The posts seem to be mostly or entirely by Chris Jagalla, of Intellogist itself, a site which analyses the different patent databases (lots of free content to look at, very useful). Chris is a dream -- he posts on the sort of very specialist topics that interest me in my profession.
The Patent Librarian's Notebook is by Michael White, of Kingston University Library, in Canada. His postings are mostly on patent classification or documentation, in both the USA and Canada.
And then there is the Green Patent Blog® with its strapline "covering intellectual property issues in clean technology". Its author is Eric Lane, an attorney in San Diego. Court cases feature strongly, and there are numerous categories to click on to see posts on for example "energy storage" or "hybrid vehicles".
No doubt there are many other excellent blogs out there, but between them these keep me aware of new developments. It's a pity that no patent office seems to have a blog -- it's a matter of checking their press releases at intervals to keep up to date, and often what is important to me (in databases, say) is slipped in without comment.
There are some lists of "top" blogs, such as 50 best patent blogs. My impression is most of the blogs in patents and inventions concentrate on US law, but there are some which specialise in particular countries, such as Spicy IP for India. There are some which specialise in particular subjects, such as the Orange Book blog on US pharmaceutical patents. Many specialists will of course find such sites more valuable than the more general sites.