There are some topics which have a word or phrase underlined for you to click. Those might be spam/ads so be careful with them. It is best to create an account and say hi to not come across those. I found a few while browsing not signed in.
They are placed there by the owners of the hosting company to help pay for this. They are not put there by the author of this site nor by any moderator or administrator. Because they are not known, I am advising caution before clicking them.
Mercury