Display titles in search engine results like Google etc is limited to 70 chars and hence last characters of posts & pages having title of more than 70 characters get trimmed from the end.
Generally this feature is provided by some SEO plugins and Premium WordPress Themes but now a new WordPress plugin allows you to enable separate post titles for single and multi post pages easily.
Disabling post title has become easy now. You can very easily disable title on certain WordPress posts or post types. This is very useful for the bloggers running personal weblogs and posting links with text. Its just like P2 Theme status updates.