when i played oblivion i heared alot of times of the thieves guild but i said "ok i will run into them eventually" but after i finished 80% of the game i said wait a minute where is the thieves guild, and started to look for them and it was very hard to find them + i needed to do some quests to find directions, it was impossible to find them if you werent looking.
on the other hand the darkbrotherhood was much easier to find but needed a password to get in, so if your not invited you cant get in.

will skyrim thieves guild will be that hard to find?

btw i read some where that some manage to find the darkbrotherhood in skyrim 20min demo while playing and ofcourse the door wanted a password, but it is THAT easy to find them? are they in riverwood or have few outposts?

It wasn't hard to find the thieves' guild at all- You couldn't walk through the main city without someone mentioning them and how to find them...

I thought they were both easy as hell to find. I was passed a note on how to find the Thieves Guild almost as soon as I started playing Oblivion, and you can hear people everywhere talking about the Dark Brotherhood and how they recruit people.

This.

I guess you really didn't have luck so you missed 'em.

The Thieves Guild is always the first thing I do in Oblivion, and it will be the first thing I do in Skyrim even before thinking about the main quest.

All you had to do was bribe a beggar or go to jail once.

Thieves Guild was one of the first things I saw & heard about in Oblivion. Gray Fox posters everywhere for one thing.