It's hard to choose the most important advancement since I became a Realtor back in 2000, but I'd say the advancement of the internet has been paramount and has served as the underlying source for other great advancements like the ease of electronic signatures and MLS sites like RealScout, Realtor.com, Zillow, and the like. Oh, and cell phones. Cell phones are pretty great when it comes to real estate.
Advancements in Real Estate
If I were to really go back to when I started making money in the real estate industry (ignoring the allowance payments from my mom for helping her put address labels on postcards), I have to stretch back to high school when, as a 15 year old looking to get some of her own money coming in, mom hooked me up with the weekend receptionist position in her office. One day a week I'd get to answer phones and put mailing labels on postcards for a variety of agents, not just my mom.
Before the Internet
When I started, the internet didn't yet exist -- at least not in any form known to the general public. We didn't even have voicemail! I took handwritten messages and distributed them to the agents' desks. The MLS consisted of books, published weekly with updates distributed as needed. The agents would review these pages (yes, physical, paper pages) to learn what was new on the market, any price changes, and what had sold. Back then if you wanted to know what was on the market beyond driving a neighborhood to look for yard signs, you talked with a Realtor.
How Far We've Come
The conveniences afforded by modern technology, and the ease at which we discover desired information is probably the largest advancement in the world of real estate, just as it is in just about every other arena of modern life, professional or personal.
These conveniences allow for faster responses and support a more responsive market. Buyers know what's on the market often at the same time as agents do (unless they're like me and have an inside track for coming soon and off market properties). Offers are constructed and signed digitally instead of sitting for hours in an office planning and constructing and wearing out wrists on disclosures. Electronic delivery of reports and disclosures have also been a huge advancement in real estate efficiency. As recently as the early 2000's if a buyer wanted to review disclosures, the buyer's agent would drive to the seller's agent's office to pick up the packet and either scan it in to email it (if their office was at the frontline of technology), or would deliver it to their client.
Despite all the wondrous advances of technology, the focused attention of a capable, professional agent working on your behalf can't be beat. Those of us who've been in it long enough to tell these stories have grown with technology, advancing and streamlining what we do to best serve our clients. We don't take for granted that we have all these fancy tools at our fingertips, but use them to enhance the value we offer to our clients.