use HTML::TreeBuilder::XPath;
my $tree= HTML::TreeBuilder::XPath->new;
my $html = <<"EOM";
HTML bla bla <tags> dies und jenes..
<a href="/user/MICHAEL" class="nick">MICHAEL</a>
<a href="/user/Wolfgang" class="nick">Wolfgang</a>
<a href="/user/daniel" class="nick">daniel</a>
EOM
$tree->parse($html);
my @nodes = $tree->findvalues("//a"); # MICHAEL Wolfgang daniel