There are several ways of establishing a web presence:
1. Website: This is where you establish purchase a domain name and fill the site with customised content. This is the more expensive route to online expression because you need to customise your webpage, you need a domain hosting service provider to provide a server for any content you which to place on your website, or which to provide access from your website. Of course you can host the website yourself but this is not an appealing proposition to people lacking the technical knowledge.
2. Blog: The low maintanence option is developing a blog. Blogs are standardised webpages that are designed for information presented in a diary or chronological format. There is no reason that the website cannot be personalised, but the tools for doing so are provided in-house. In as much as the content is hosted by the blogging company, you are dependent on their format options.
3. Social Networking Member Sites: The last option is online websites that provider you a member page so that you can relate to other members on the basis of shared interests or activities. These types of pages perhaps offer the most compelling service because of their ability to capture the person information of members. These websites offer the most compelling model for advertising.
The best option to suit your needs depends on what you want to achieve. Some flexibility is provided, in the sense that you might secure a domain name, only to redirect inquiries to that address to your blog pages. The most important reason for securing a web domain name is to ensure ownership of your name - and that can be important if you want to offer some sense of continuity, for the sake of networking or branding. Redirecting a blog allows you to capture the low maintenance benefits of a blog at the same time, and because you can always move the content, you dont risk loosing business when you change blogs or domain names. For these reasons a website is important for anyone intending to establish commercial goals for their online presence.
If your intent in merely to offer friends a way to catch up with what you are doing and to interact with them, or to meet new people, then some type of social networking based on shared activities or interests makes alot of sense. These sites tend however to not provide the same options for self expression, so you might prefer a combination of social networking and blogging tools.
The future belongs to those companies that provide an integrated and comprehensive service. eg. Google, Yahoo and Facebook appear to be the leaders in the social networking stakes.