user6174: It seems like LEGO is the official way to write it, but folks seem to like to write Lego or lego.

user52: I'm pretty sure the Lego company can't dictate how people spell their name. Trademark law doesn't forbid you from speaking about a company or product and doesn't impose any restrictions on the users of the site.
To the extent that the site itself wishes to be friendly towards Lego, and wishes to use the name Lego in its name, the site needs to respect Lego's own guidelines. But that is because Lego is allowing the site to use their name. If bricks.stackexchange.com weren't called "Lego Answers" then the Lego group would have no possible reason to expect any particular treatment of its trademarks.
In short: I think the site should do whatever Lego wants with regards to the trademark. However, I'm certain that the users, that is, people posting Qs and As, do not need to learn the Lego trademark guidelines and follow them. That isn't what trademarks do and that isn't how language works. Spell it however you want. 

user56: See also: FYI - informed LEGO of the existence of bricks.se - where TLG responded with:

Also LEGO needs to be written always in capital letters and should never stand alone so LEGO bricks, LEGO Sets...

Our general approach here has been that we don't go around capitalising every single instance (in the same way that we might not purge every single instance of LEGOs), but if you're editing a post for some other reason (spelling, formatting, etc.) then please do fix them up.
Although I'm sure you'll find examples where I've only fixed up LEGO...

6174: <p>It seems like <a href="https://bricks.meta.stackexchange.com/questions/9/do-we-use-lego-or-legos">LEGO is the official</a> way to write it, but folks seem to like to write <code>Lego</code> or <code>lego</code>.</p>
 52: <p>I'm pretty sure the Lego company can't dictate how people spell their name. Trademark law doesn't forbid you from speaking about a company or product and doesn't impose any restrictions on the users of the site.</p>

<p>To the extent that the site itself wishes to be friendly towards Lego, and wishes to use the name Lego in its name, the <em>site</em> needs to respect Lego's own guidelines. But that is because Lego is allowing the <em>site</em> to use their name. If bricks.stackexchange.com weren't called "Lego Answers" then the Lego group would have no possible reason to expect any particular treatment of its trademarks.</p>

<p>In short: I think the <em>site</em> should do whatever Lego wants with regards to the trademark. However, I'm certain that the users, that is, people posting Qs and As, do not need to learn the Lego trademark guidelines and follow them. That isn't what trademarks do and that isn't how language works. Spell it however you want. </p>
 56: <p>See also: <a href="https://bricks.meta.stackexchange.com/q/73/56">FYI - informed LEGO of the existence of bricks.se</a> - where TLG responded with:</p>

<blockquote>
  <p>Also LEGO needs to be written always in capital letters and should never stand alone so LEGO bricks, LEGO Sets...</p>
</blockquote>

<p>Our general approach here has been that we don't go around capitalising every single instance (in the same way that we might not purge every single instance of LEGOs), but if you're editing a post for some other reason (spelling, formatting, etc.) then please do fix them up.</p>

<p>Although I'm sure you'll find examples where I've only fixed up LEGO...</p>
