Need help interpreting bleak house output

Hello! I haven't been able to find much on how to interpret the
output from bleak house. I got this after exercising my app for a
little while. Does anybody see anything suspicious?

342727 total objects
Final heap size 342727 filled, 410045 free
Displaying top 20 most common line/class pairs
257845 __null__:__null__:__node__
  27971 __null__:__null__:String
   2160 /usr/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_view/
helpers/asset_tag_helper.rb:449:String
   1930 (eval):3:String
   1089 /usr/lib/ruby/gems/1.8/specifications/actionpack-2.0.2.gemspec:
15:String
   1045 /usr/lib/ruby/1.8/yaml.rb:133:String
    987 /usr/lib/ruby/gems/1.8/specifications/
actionpack-1.13.6.gemspec:13:String
    981 /usr/lib/ruby/gems/1.8/specifications/
actionpack-1.13.3.gemspec:13:String
    945 /usr/lib/ruby/gems/1.8/specifications/
activerecord-2.0.2.gemspec:15:String
    927 /usr/lib/ruby/gems/1.8/specifications/
activerecord-1.15.6.gemspec:13:String
    915 /usr/lib/ruby/gems/1.8/specifications/
activerecord-1.15.3.gemspec:13:String
    909 __null__:__null__:Regexp
    807 /usr/lib/ruby/gems/1.8/specifications/rubygems-
update-1.1.1.gemspec:15:String
    735 /usr/lib/ruby/gems/1.8/specifications/net-ssh-1.1.2.gemspec:
15:String
    727 __null__:__null__:Class
    720 /usr/lib/ruby/gems/1.8/specifications/rails-2.0.2.gemspec:
14:String
    654 /usr/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/
active_record/attribute_methods.rb:160:__node__
    605 /usr/local/lib/site_ruby/1.8/rubygems/specification.rb:
557:Array
    576 /usr/lib/ruby/gems/1.8/specifications/rubygems-
update-1.0.1.gemspec:15:String
    538 /usr/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/
active_support/core_ext/module/introspection.rb:31:String

Basically, my two mongrels use about 40MB each when started, and after
a day or two, they grow to almost 200MB. The main function of the
site is to display items (www.massstreetmusic.com), and there are
around 2500 items with a few pictures each (and yes, I've gotten rid
of RMagick). Maybe this usage is normal for a site of this size and
traffic (around 5,000 page views per day), but I'd appreciate the
opinion of others.

Thanks!

-Kyle

Hop into #fauna on Freenode IRC. The author of Bleahouse, Evan Weaver
(evn), can help you out.

--Jeremy