This is a security protection that is now built into Rails 3. It prevents problems with XSS (cross-site scripting).
If you add raw, you will get the desired result.
<% @posts.each do |post| %>
<h1><%=raw post["name"]%></h1>
<p><%=raw post["body"] %></p>
<p><%=raw post["timestamp"]%></p>
<% end %>
, HTML-, , , .
Edit:
: raw, sanitize helper. <%=sanitize post["name"], :tags => "p" %>, <p>.