This should not be hard to do, but it seems that sometimes it is. I have just been looking at a webpage from a national organisation in Australia (and I won't out them), it is about exciting things coming up, and I thought I would tweet the page. There was no share option.
Yes, I know I could have copied and pasted the information. It isn't hard, and often I do this. In this instance that the page was not easily sharable undercut what they seemed to be trying to achieve.
This is also a great page showing lots of social media options, but I can't find the share on this page either. I really like the way the social media is brought together on this page - but it still needs to be shareable.
In case you are thinking I am being unreasonable in wanting to share webpages - have a look at how easy NASA makes it with share right next to search (on every page at the top right). They also have an amazing range of share options.