Lately I've been thinking a lot about building a website/blog/community oriented site. However I can't decide if it's a good idea to build it using Wordpress as a base.
I've been reading around the Internet, and I've seen that many users have trouble with Wordpress using lot of CPU and other resource related problems.
So, what do you think? Is it wise to actually build an application based on Wordpress? Or it would probably lead to undesired results?
Any opinions would help.
Well that's basically what Wordpress is for :P I've never heard of any issues with Wordpress using lot of CPU and other resource related problems. It seems perfect for what you want to do. Are you familiar with PHP?
If you to get really farther than a blogging software, maybe you can have a look at more generic CMSes.
I kinda like Drupal (which has a lot of plugins that can help you do almost whatever you want on your site) ; as a reference point, it is used by many quite big sites, so, if correctly configured, can hold a bit of load.
Just a remark : you might need at least a couple of day to learn how to use it well, because it is quite rich, has lots of features, and you will probably want to have a look at many modules, to get the ones you need/like. (But that would be true for any CMS, I guess)
Any moderately-sized site should have a cache in front of WordPress. WP Super Cache is one of the more popular ones. Basically, WordPress should be generating pages only when needed. In all other cases, the page should be served from cache.
WordPress is quite flexible once you get the hang of its WordPress Loop, Page Templates and how to create a customised homepage. Using some plugins, such as the Page Redirect To and Custom Taxonomy, you can have a pseudo-CMS. There are also widgets and plugins that let WordPress mimics CMS-like behaviour, such as listing all sub-pages within a pages, customize how categories are shown and etc.
If you can handle the WordPress loop and use Page Templates, WordPress is okay to build on-top of. However, its database schema is quite confusing. Depending on your goals, you may want to use CodeIgniter or something else.
Wordpress is open, so you can use it if you want.
But I think building a plugin and hook to Wordpress's main feature is a better ideal.
And btw, What is the meaning of "application" you are developing.
I recommend using WordPress MU with the BuddyPress plugin for building a community site. BuddyPress is actively maintained, and the set of features are comparable to the basics of Facebook (wall, groups, pages, etc.). Not to mention all of the plugins. Also, with a little extra effort, you can have bbPress (WP forum software) in your community app too. I am working on a big project using each of these products right now, and it has been much less of a nightmare than the times I've done something similar in the past, using other community apps or forum software.