The key to scalability is infrastructure. That could mean building better software systems to manage growth or it could mean hiring more people.
If you have a $10K business and you want to grow it to $100k, you must first consider what you will need to manage the business once it reaches $100k. If you do not plan properly, you will create bottlenecks and inefficiencies.
For example, you could plan to acquire 100 new web sites with proven traffic and revenue, but if you cannot manage and promote those web sites properly, you will probably lose a lot of potential business and miss a lot of opportunities to maximize revenue.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -- Benjamin Franklin