I think about the sentence “put the right man in the right job”. This also apply to digital device not only human.
Nowadays, I mainly share my thoughts and stories to various social networks via mobile phones. Although the mobile phone now so advanced in hardware, software and internet connection, I discover that not all actions are well doing on mobile phone especially its browser! Not yet enough to handle such a complex HTML5, CSS, Flash, Overlay content, Complex interaction, etc. Easy to crash and take too much times to load. I summary what I think which device did best (with Social networks) below :-
Best with mobile phones are Upload photo (that just take), Check in to places, Reply comment, Like on topics
Better use Notebook/Desktop are Share other website story direct URL, All features that only available via desktop mode (not available in mobile apps).
Even I not mentioned Tablets, their browser also still not be able to replace Notebook/Desktop one too.