How do you use the # when writing on Facebook or twitter?

[SuperSam]

I keep seeing this # trend everywhere on social networks. Is there a rule to using it or can you just literally wrote anything that fits your situation/mood after a #? Am slightly confused?

[James]

with the keyboard

[Ian]

The hashtag (#) is generally used for trending topics, but you are correct, you can put anything after it. On twitter (and now other social networking sites), when you put, for example, #ilovepie, if someone searches #ilovepie they will find your post.

[Harsimran Singh]

Don't know about Facebook, but it is used on twitter to tag your post. People searching for this tag will read your tweet. You can search tags by using the search box. example- Sports, basketball, facebook etc. and you will get redirected to all the tweets with this tag.