'For your information' (abbreviated to FYI in slang) is often written, rather than said. It is a useful phrase if you just want to share an update on a website, or something similar. At work, people sometimes entitle emails with 'FYI' to share a document or discussion.
The only negative connotations that I can think of are:
1) It can seem a little bit rude outside a work situation or offline, and is probably best to avoid in speech.
2) 'FYI' is sometimes used in slang to rudely inform someone of something. It is often used sarcastically by grumpy teenagers. :) E.g. "For your information, I had a great day!"