Yes, the string after a domain name (called a query string) can affect SEO, depending on how it's used and managed. Here are a few key points:

1. Indexing Issues

• Search engines treat URLs with query strings as separate URLs, even if they lead to the same content. This can result in duplicate content issues, where multiple versions of the same page compete with each other in search results.
• If a query string doesn't change the content of the page (e.g., tracking parameters), it should be handled correctly to avoid indexing problems.

2. URL Structure and Readability

• Clean and descriptive URLs are preferred for SEO. For example, /services/dental-care is more user-friendly and SEO-friendly than /?v=2c18c36508d1.
• Query strings that don't convey meaningful information can make URLs look spammy and discourage users from clicking.

3. Crawl Budget

• Query strings can waste your crawl budget, especially if they create unnecessary URL variations. Google might crawl these variations instead of more important pages.

4. Canonical Tags

• If query strings are necessary (e.g., for tracking or filtering), use canonical tags to point search engines to the primary version of the URL. This ensures only the preferred version is indexed.

5. Google Search Console

• You can configure how Google handles parameters in your URLs using the URL Parameters tool in Google Search Console. However, this tool should be used cautiously and only if necessary.

Recommendations:

• Minimise query strings in URLs wherever possible.
• Use clean, keyword-rich URLs for important pages.
• Implement canonical tags to consolidate duplicate URLs caused by query strings.
• Use tracking tools like Google Tag Manager to avoid appending tracking parameters to URLs.
• Regularly monitor and audit your URLs to ensure they are optimised for SEO.

For example (https://domainname.com.au/?v=2d18c56578d1), if the query string doesn't change the content but is for tracking or versioning, it might be worth addressing to avoid potential SEO issues.