How do URL parameters influence website usability & user experience, & how can these factors be balanced for SEO?

URL parameters can definitely impact website usability and user experience, as well as SEO. It's all about finding the right balance.

From a usability perspective, having too many parameters in a URL can make it really long and hard to read. These complex URLs are also difficult for users to copy/paste or share with others. Additionally, improper use of parameters can break the normal back/forward navigation behaviour in browsers, which is confusing for visitors.

At the same time, you have to consider SEO factors. Search engines may treat URLs with different parameter combinations as separate pages, which can lead to duplicate content issues if not handled correctly. An overabundance of parametrized URLs can also make it hard for search engine crawlers to effectively navigate and index your site.

So how do you balance all this? First, minimize unnecessary parameters - only use them when absolutely required for functional purposes. Then implement proper canonicalization using canonical tags or rel="canonical" to show search engines the main version of pages with parameters.

Using URL rewriting techniques to create clean, keyword-rich URLs without parameters is also really helpful for both users and SEO. Leveraging robots.txt can also control how search engines crawl parametrized URLs.

Ultimately, you'll want to monitor user behaviour data and SEO performance, then adjust your URL parameter strategy over time to find the right balance for your particular website and audience. However, being mindful of usability and SEO implications from the start is key.