I have been acquiring a list of useful websites for geeks and thought I would post it here in case it is of use to anyone else. This post is a work in progress. More may be added over time.
Trello – A wonderful way to plan and organise projects. Highly flexible and free for basic use
Appear.in – A nice alternative to Skype. Free for up to four person meetings. Allows camera, voice, screensharing and integration with Trello
Slack – Well known and very useful, near real-time multi-person conversations without interrupting people who are deep in thought
LucidChart – Excellent diagram software. The basic level allows for simple flowcharts, venn diagrams and the like, while the paid plans cover things such as product mock ups and database design (with the ability to export SQL table creation code as a nice bonus)
Github – useful for so many things beyond traditional code repos, some places are even putting their laws on Github these days
Game-Icons.net a very handy source of icons. Useful for games or other projects. The icons can also be coloured and customised in the icon editor which can be reached by clicking on any icon and using the menu to the left when the icon displays in large format.