Oh yes, I did actually realise that. Thank you though.

I worded it badly. I should have been clearer in that I was following on from solutionyogi's argument about readability.

The compiler example is a bit on the ugly side, wouldn't you say? To then access 'keywords', it becomes

  ...
  .Where(anon => anon.keywords[0] == "verybadexample")
  .Select(anon => anon.post);

What I should have said was that I'm not sure how you would scope things in the same way as the 'let' clause when using extension methods with the same level of readability.

Like this:

  var thing = 
    from x in stuff
    let derp = x.herp
    select { x.name }

Equals this:

  var thing = stuff.Select( x => {
    var derp = x.herp;

    return new { x.name };
  } );

edit: formatting.

I think each have their place, but this absolutely enrages me:

  var things = ( from x in thingList select x ).ToList()