Filtering:

You can filter the posts using the controls in the right-hand sidebar. You can select only those posts for a particular county e.g. London or you can select only those posts for a particular  location type e.g. Cathedrals. It's very easy to do.

Quoting:

You can quote previous comments by pressing the 'Quote' button or you can do it manually as follows:

If you want to insert part or all of a previous comment as a quote then mark (block) the text you want to quote then insert it into your comment.

In front of the quoted text put this: <blockquote>

At the end of the quoted text put this: </blockquote>

That should display the text as a 'Quote'.

You should end up with something like this:

<blockquote>This is the quoted text</blockquote>